Field
Embodiments of the present disclosure generally relate to forming a pixel capacitor structure with high capacitance and low leakage. More particularly, embodiments of the disclosure relate to methods for forming a pixel capacitor structure with high capacitance and low leakage for liquid crystal display (LCD) applications.
Description of the Related Art
Display devices have been widely used for a wide range of electronic applications, such as TV, monitors, mobile phone, MP3 players, e-book readers, and personal digital assistants (PDAs) and the like. The display device is generally designed for producing desired image by applying an electric field to a liquid crystal that fills a gap between two substrates (e.g., a pixel electrode and a common electrode) and has anisotropic dielectric constant that controls the intensity of the dielectric field. By adjusting the amount of light transmitted through the substrates, the light and image intensity, quality and power consumption may be efficiently controlled.
A variety of different display devices, such as active matrix liquid crystal display (AMLCD) or an active matrix organic light emitting diodes (AMOLED), may be employed as light sources for display devices which utilize touch screen panels. In the manufacturing of TFT devices, an electronic device with high electron mobility, low leakage current and high breakdown voltage, would allow more pixel area for light transmission and integration of circuitry, thereby resulting in a brighter display, higher overall electrical efficiency, faster response time and higher resolution displays. In some devices, a dielectric layer is placed between a pixel electrode and a common electrode to form a capacitor that may store electric charges when the TFT devices are in operation. The capacitor as formed is required to have high capacitance as well as low leakage to provide desired electrical performance of the TFT devices. As the capacitance may be adjusted by changing of the dielectric constant of the dielectric layer formed between the pixel electrode and the common electrode and/or thickness of the dielectric layer. For example, when the dielectric layer is replaced with a material having a higher dielectric constant, the capacitance of the capacitor will increase as well. However, selection of the material of the dielectric layer not only affects the capacitance of the capacitor, incompatibility of the material of the dielectric layer to the electrodes (either to the pixel electrode or to the common electrode) may also result in film structure peeling, poor interface adhesion, or interface material diffusion, which may eventually lead to device failure and low product yield.
Therefore, there is a need for improved methods for forming a capacitor with high capacitance and low leakage as well as a good interface control for manufacturing TFT devices that produce improved device electrical performance.